3A分辨率绿豆胰蛋白酶抑制剂Lys活力碎片—牛胰蛋白酶(MBILF-BTRY)复合物的晶体结构分析和分子模型

用分子置换法成功地解得了MBILF-BTRY的晶体结构,并得到了它的立体结构模型。绿豆胰蛋白酶抑制剂属于絲氨酸蛋白酶抑制剂中结构最复杂的Bowman-Birk型抑制剂。这一类型抑制剂的立体结构以前尚未见报道。MBILF-BTRY复合物晶体的晶胞参数为a=62.99,b=63.54,c=69.70,α=β=γ=90°,空间群为P2_12_12_1,复合物分子量约为27500daltons。用理学电机的Ru-300型转靶X光机及AFC-5型四园衍射仪收集了分辨率为3范围内的独立衍射点5142个。以蛋白质数据库所取得的牛胰蛋白酶分子的座标为     

绿豆胰蛋白酶抑制剂-猪胰蛋白酶复合物的晶体学研究

本文报道利用微量静置法培养出绿豆胰蛋白酶抑制剂-猪胰蛋白酶复合物可供X射线衍射分析的单晶体。晶体衍射分辨率2.7。晶体学参数测定结果为四方晶系,空间群1422,晶胞参数a=b=122.4(2),c=113.4(2)()。晶体密度1.20g/cm~3,溶剂含量36％,每个结晶学不对称单位含一个复合物分子。     

数学史的劃期 数学的萌芽时期——关肇直先生在中国科学院数学研究所数理邏輯室举办的“数学基础讲座”上的报告

为什么要讲数学史呢?上一讲談过数学基础是要研究数学的对象、性质、特点及其发生发展規律。了解数学史就是想通过它未了解数学基础的问题。我们的数学史与西方资产阶級学者的数学史有根本的不同。这是由于它与阶级社会有密切关系之故。西方好多数学史书刊有好多片面性甚至毒素,例如把数学史看成史料的堆积,看成个別天才人物(数学家)的創造,还有好多人的学术观点有錯誤,甚至史料的錯誤。例如,在西方数学史中有这样一个故事,讲到19世紀的大数学家欧拉,他本来在数学活动中方向明确,把数学与力学等相结合。然而西方却有一个传說,说狄德罗有一次作无神论的报告,欧拉写了一个很复杂的教学公弌,說我用这公式可証明神存在,狄德罗给吓跑     

0.3 nm分辨率绿豆胰蛋白酶抑制剂Lys活力碎片—牛胰蛋白酶(MBILF-BTRY)复合物的晶体结构分析和分子模型

Crystal structure of MBILF-BTRY complex was successfully solved by molecular replacement method and its 3-dimensional molecular model was thereby derived. Mung bean trypsin inhibitor belongs to Bowman-Birk inhibitor group, which is by far the most complicated among the ten fundamental groups of serine protease inhibitor. Neither the 3-dimensional structure of Bowman-Birk inhibitor group nor the stereoscopic conformation of its complex with protease has ever been reported. The crystallographic data of MBILF-BTRY complex are found to be a=....     

STUDIES ON ORGANOMETALLIC COMPOUNDS OF TITANIUM,ZIRCONIUM AND HAFNIUM——THE CRYSTAL AND MOLECULAR STRUCTURES OF OXO-BRIDGED TETRAKIS(CYCLOPENTADIENYL)BIS (o.TOLYL)AND TETRAKIS(METYLCYCLOPEN-TADIENYL) BIS(p-TOLYL)BINUCLEATED ZIRCONIUM COMPOUNDS

This paper reports the crystal and molecular structures of tetrakis (cyclopentadienyl) bis(o-tolyl)-μ-oxo-dizirconium [dimer (Ⅰ)] and tetrakis (methylcyclopentadienyl) bis (p-tolyl)-μ-oxo-dizirconium [dimer (II)]. Both of them belong to monoclinic system and possess the same spacegroup C_2~5h- 2_1/a. The cell dimer (Ⅰ) containing four molecules is defined by a=19.122A,b=16.319A, c = 9.296A, β= 92°1′; the cell dimer (Ⅱ) containing two molecules is defined bya = 20.076A, b = 8.205A, c = 10.016A, β= 104°41′. The important difference of molecular configurations between the two dimers lies in thatthe dimer (Ⅰ) has no symmetry center and its Zn-O-Zr oxo-bridge presents a slightly bentconfiguration while the dimer (Ⅱ) takes the oxgen atom as a symmetry center and its oxo-bridge present linear linkage. In accordance with the above-mentioned molecular configuration, steric effect and elec-tronic structure have been further discussed.     

CRYSTALLIZATION AND PRELIMINARY CRYSTALLOGRAPHIC DATA OF THE MUNG BEAN INHIBITOR

The trypsin inhibitor from mung bean has a molecular weight of 7984, consisting of two active domains and seven disulfide bonds. It belongs to the Bowman-Birk inhibitor. This inhibitor has been crystallized in two crystalline forms either by dialysis or by batch method. One is tetragonal with unit cell of symmetry P4_122(or P4_322) and dimensions a=b=49.21, c=158.07, each asymmetric unit containing three molecules. Another is orthorhombic with unit cell of symmetry P2_12_12 and dimensions a=39.65, b=57.18, c=52.02, each asymmetric unit containing two molecules.     

绿豆胰蛋白酶抑制剂晶体生长及晶体学参数测定

从绿豆中提取的胰蛋白酶抑制剂,分子量为7984,具有两个活性中心,7对二硫键,属于Bowman-Birk抑制剂类型。用透析法和静置法生长出四方双锥和斜方柱两种晶体。用X1线旋进照相法测定它们的晶胞参数。四方双锥晶体属四方晶系,空间群P4_122(或P4_322),a=b=49.21(?),c=158.07(?)。每个晶体学不对称单位包含三个分子。斜方柱晶体属正交晶系,空间群P2_12_12,a=39.65(?),b=57.18(?),c=52.02(?)。每个晶体学不对称单位包含两个分子。     

THE CRYSTALLOGRAPHIC STUDY OF THE COM PLEX OF THE LYS ACTIVE FRAGMENT OF THE MUNG BEAN TRYPSIN INHIBITOR WITH BOVINE TRYPSIN

The Lys fragment of mung bean trypsin inhibitor can combine with bovine trypsin to form a complex at an equal molar ratio. The single cxystals of the complex were obtained by using the micro-still-setting method and the X-ray diffraction extended to 1.8 resolution. Its space group is P2_12_12_1 wlth cell dimensions α=62.9(1), b=63.4(1) and c=69.7(2). There is one complex molecule in a crystallographic asymmetric unit.     

绿豆胰蛋白酶抑制剂Lys活力片段-牛胰蛋白酶复合物的晶体结构测定——分子置换法及3分辨率电子云密度图

本文以修正过的牛胰蛋白酶分子的坐标为模型,应用旋转函数法和平移函数法成功地求得了牛胰蛋白酶分子在绿豆胰蛋白酶抑制剂Lys活力片段(以下简称MBILF)-牛胰蛋白酶(以下简称BTRY)复合物晶体晶胞中的取向和位置。从正确放置于MBILF-BTRY复合物晶胞中的BTRY分子的坐标出发,用Sim权重方法算得的一套相角作为MBILF-BTRY复合物的相角,以2丨F_0|—丨F_(?)丨为系数所得到的3分辨率的电子密度图中,除了投入计算的BTRY分子本身的电子密度外,在BTRY的活性部位附近可以清晰地看到MBILF分子所对应的电子密度及其边界,抑制剂片段的线度约为15×15×25。     

钛、锆、铪有机化合物的研究——四(环戊二烯基)二(邻甲苯基)和四(甲基环戊二烯基)二(对甲苯基)-μ-氧合二锆的晶体结构和分子结构

本文报道了四(环戊二烯基)二(邻甲苯基)-μ-氧合二锆[二聚物(Ⅰ)]和四(甲基环戊二烯基)二(对甲苯基)-μ-氧合二锆[二聚物(Ⅱ)]的晶体结构和分子结构。二者均属单斜晶系,具有相同的空间群C_(2h)~5-P (21)/a。二聚物(Ⅰ)晶胞中含有四个分子,晶胞参数为a=19.122,b=16.319,c=9.296,β=92°1′。二聚物(Ⅱ)晶胞中含有两个分子,晶胞参数为a=20.076,b=8.205,c=10.016,β=104°41。两种二聚物分子构型的主要差别在于:二聚物(Ⅰ)不具有对称中心,Zr—O—Zr氧桥稍呈弯曲;二聚物(Ⅱ)以氧原子为对称中心,Zr—O—Zr氧桥呈直线型,据此讨论了空间效应和分子的电子结构。